A hearing aid device is a device for aiding an individual in regard to its hearing. It may be a hearing aid or hearing prosthesis for compensating a hearing loss of its user. It may also be a hearing protection device which helps individuals to hear without damage in noisy environments. Such a device may transmit speech and attenuate noise by selective amplification. The occlusion effect is an effect experienced by individuals when an ear canal is fully or partially closed by an occluding object. In such a condition, the own voice of the individual and other body conducted sounds are perceived by him- or herself unnaturally loud. The earpiece of a hearing aid device can be such an occluding object. Active occlusion control is a method for reducing the occlusion effect actively. Actively means by destructive interference, i.e. emitting a kind of anti-sound. A passive occlusion control (or passive occlusion reduction) would be the provision of a large vent. However, hearing aids with a large vent are prone to feedback and cannot deliver loud low-frequency sound due to leakage from the canal to the outside and cannot provide good sound cleaning due to leakage from the outside into the canal. Providing hearing protective devices with a large vent renders them useless because low-frequency noise can pass without substantial attenuation through the vent. Occlusion is not to be confused with ampclusion. Users of hearing aid devices may perceive their own voice as being unnatural due to its amplification by the hearing aid device. Ampclusion can be counteracted by reducing the hearing aid device amplification in the frequency range of the users voice. Both occlusion control and ampclusion control aim for providing an own voice perceived as more natural.
U.S. Pat. No. 6,035,050 by Weinfurtner discloses a method for determining optimum parameter sets in a hearing aid. During an optimization phase an optimal user specific parameter set is allocated by selecting one of several trial parameter sets available.
WO 2004/021740 A1 by Rasmussen et al. discloses a method for counteracting the occlusion effect of an electronic device like a hearing aid. Sound conditions in the cavity between the ear piece and the tympanic membrane are determined. The transmission characteristics of the transmission path to the receiver counteracts the occlusion effect.
WO 2006/037156 A1 by Mejia et al. discloses an acoustically transparent occlusion reduction method. An electro-acoustic feedback network produces phase cancelling sounds in the ear. The integration with a hearing aid improves the user's perception of own voice.
WO 2008/017326 A1 by Nordahn discloses a method for in-situ occlusion effect measurement. A hearing aid comprises a microphone for external sounds and a microphone for sounds in the occluded ear. An occlusion effect value is produced from the difference. The user may read a text passage or vocalize a sound such as /iii/ or /uuu/. The hearing aid may be fitted based on the occlusion effect value.
US 2009/238387 by Arndt et al. discloses a method for actively reducing occlusion. A transducer transmission function, which is defined for the transmission path from the input of a receiver via the auditory canal to the output of a microphone, is subjected to an automatic plausibility check.
US 2009/274314 by Arndt et al. discloses a method for determining a degree of closure in hearing devices. Arndt mentions active occlusion reduction. An effective vent diameter specifies the degree of closure. An interpretation of this value is easily possible by a hearing device acoustician.
WO 2010/083888 A1 by Rung et al. discloses a method for in situ occlusion effect measurement. An external sound pressure of an occluded ear is measured by the microphone of a BTE hearing aid. The sound pressure at the eardrum is measured by a hearing aid receiver.
WO 2012/003855 A1 by Rung discloses a method for measuring the occlusion effect of a hearing aid user. The diameter of a ventilation channel may be increased to reduce the occlusion effect. Leakage between bands is regarded in the measurement.